1. Field of the Invention
The present invention relates to a design data creating method, a design data creating apparatus and a computer readable information recording medium.
2. Description of the Related Art
For example, as means for designing electronic circuits, an electronic circuit design CAD apparatus (simply referred to as a circuit design CAD, hereinafter) exists for designing an electronic circuit such as a printed circuit substrate (i.e., PCB).
An operation speed of a device used in an electronic circuit has been increased along with a progress of the related technology. In a recent electronic circuit, since many devices of increased operation speeds are used, such a design as that considering countermeasures for electronic noise is required. In order to proceed with a design considering countermeasures for electronic noise with the use of the above-mentioned circuit design CAD, a circuit designer may give ‘design constraint requirements’ to a packaging designer, in any one of the following two methods (1) and (2), in the related art.
It is noted that, the above-mentioned design constraint requirements mean constraint requirements required for carrying out a packaging design considering electric noise, for example. Specifically, constraint requirements concerning a wiring width, a wiring length, a wiring route or such, may be included, for example.
(1) The circuit designer creates a packaging design instruction sheet, and gives it to the packaging designer.
In this method, as shown in FIG. 1, the circuit designer creates the packaging design instruction sheet as a separate document from data created by means of the circuit design CAD (i.e., EDIF data, described later, or such), and manages the same. In this method, the design constraint requirements are shown only on a paper sheet of the packaging design instruction sheet as shown in FIG. 2, and the packaging designer carries out a packaging design with reference to this packaging design instruction sheet.
(2) The design constraint requirements are described in a schematic circuit diagram itself, in a form of comments.
In this method, as shown in FIG. 3, the circuit designer manually writes the design constraint requirements in the schematic circuit diagram itself in the form of comments, other than the above-mentioned packaging design instruction sheet. As a result, the packaging designer can easily recognize the constraint requirements when referring to the schematic circuit diagram itself. The packaging designer refers to the above-mentioned packaging design instruction sheet and the design constraint requirements written in the schematic circuit diagram in the form of comments, and carries out a packaging design according to thereto. Furthermore, the circuit designer himself or herself can use the design constraint requirements directly written in the schematic circuit diagram in the form of comments, for checking after the packaging designer has completed the packaging design.
In the method (1), the above-mentioned packaging design instruction sheet is handled separately from data, handled by the circuit design CAD or the packaging design CAD, and is created by means of word-processor software or such. The packaging designer prints out the packing design instruction sheet by means of a printer, to confirm the contents thereof, or, causes the contents thereof to be displayed on a monitor of a personal computer by means of software, different from the software of the circuit design CAD itself or the packaging design CAD itself. That is, there is no linkage given with the CAD software.
In the method (2), as shown in FIG. 3, since the work of writing the design constraint requirements in the schematic circuit diagram in the form of comments is made manually, man hours are required accordingly. The comments thus written in the schematic circuit diagram are ordinary comment data, and thus, also no linkage is given with such a type of design constraint requirements which are set in CAD data such as EDIF data for the purpose of DRC described below.
That is, the design constraint requirements written in the form of comments are managed separately. Accordingly, for a case where the same design constraint requirements should be set uniformly in each of many similar circuits, the same comments should be written in each of these similar circuits separately. In this case, for when the thus-given design constraint requirements are modified after that for example, all the corresponding comments should be modified separately in the same manner one by one. As a result, man hours are required, and also, a possibility of human error should be considered.
Japanese Laid-open Patent Applications Nos. 2002-157285, 11-353350 and 7-93013 disclose related arts.